Intelligent Packet Forwarding Data Distribution Network Packet Brokers and Network Taps

Network Packet Broker and Network Tap Data Frame Forwarding Process

The host operates in a half-duplex state, so CSMA/CD is used to detect whether the link is idle. Preamble is used to synchronize the receiver, and SFD is used to indicate the start of the frame. Leading codes are seven bytes of binary 1,0 alternating code, that is, 1010...There are 56 of them.The frame head delimiter is 1010 bytes long...A binary sequence whose function is to cause the receiver to locate the first position of the frame.

Devices in the same conflict domain will receive the data frames sent by host A. Only the gateway (RTA) processes this data frame and is based on forwarding. In this case, host A sends A data frame to the Shared Ethernet, and all devices in the network receive that frame.After the device receives the frame, it will first conduct FCS verification.If the FCS check fails, the frame is discarded immediately.For frames that pass FCS validation, the device checks the destination MAC address in the frame.If the destination MAC address in the frame is different from its own MAC address, the device discards the frame, and if it is the same, it continues processing.During processing, the head and tail of the frame are stripped (that is, unsealed), and the valid datagram is sent to the corresponding protocol module in the network layer for processing according to the value of the type field in the frame header.

The gateway checks to see if it has a route entry to the destination network. If there is a forward path, add a new two-tier header and footer to the packet and continue forwarding. After rt-a receives the datagram, the network layer will process the datagram.Rt-a first checks the integrity of the IP data packet header based on the checksum field in the IP header information, and then checks the routing table based on the destination IP address to determine whether the packet can be forwarded to the destination.Rt-a must also process the value of TTL.In addition, the message size must not exceed the MTU value.If the packet size exceeds the MTU value, the packet is partitioned.

After the network layer is processed, the message is sent to the data link layer for re-encapsulation, called a new data frame, whose header encapsulates the new source MAC address and destination MAC address.If the current network device does not know the MAC address for the next hop, it will use ARP to get it.

Several Commonly Used Packet Forwarding Mechanisms:

1- Process Switching
2- Fast Switching
3- Cisco Express Forwarding short as CEF
4- Optimum and Distributed Switching
5- Netflow Switching

NT-FTAP-32QCX Network Packet Brokers(NPBs) Packet Forwarding Application(sent the right packet to right tools)

NT-FTAP-32QCX Network TAP NPB.pdf